1. Field of the Invention
The present invention relates to a document handling device having a support frame with four legs, at least one of which is height-adjustable.
2. Background of the Invention
A document handling device, e.g. a printer, a copier or a scanner, typically comprises a number of mechanical components that need to be perfectly aligned and adjusted relative to one another or to a recording medium that is to be scanned or printed on in the device. Examples of such mechanical components are a guide rail for a reciprocating printhead carriage of an ink jet printer, a rotating mirror or an LED array in a laser printer, a scanning mirror assembly and/or a CCD array in a scanner and the like. Since both, the transport and guide device for the recording medium, e.g., paper, and the mechanical components are directly or indirectly mounted on the support frame, even a slight torsional deformation of the support frame may deteriorate the alignment and/or adjustment of the mechanical components, and this will have negative consequences on the function of the device, i.e. the quality of printed or scanned images.
A torsion of the support frame is typically induced when the document handling device is installed on an uneven floor. A well-known counter measure for avoiding such torsion is to precisely level the support frame by compensating for the unevenness of the floor, so that the frame will be precisely level and torsion-free.
U.S. Pat. No. 4,637,581 discloses a self-levelling support frame.
JP 04/244 880 A discloses a printer, wherein any strain of a printer case is detected with a strain gauge. When the strain gauge detects an installment state where the printer case is likely to be subject to excessive bending force or torsional force, the strain gauge causes the control system of the printer to prevent printing operations until the strain has been relieved.